by David Jackson and Kelly Kennedy, USA TODAY

by David Jackson and Kelly Kennedy, USA TODAY

WASHINGTON -- President Obama called Sunday for a "transformation" of the nation's gun laws, saying last week's deadly shooting at the Washington Navy Yard echoes too many other killings across the United States.

"Our tears are not enough," Obama said during a memorial service for the victims and their families. "Our words and our prayers are not enough. ... We are going to have to change."

Gun violence in America "ought to obsess us," Obama said.

Acknowledging that a gun-control package he proposed earlier this year has stalled in Congress, Obama said the change won't come from Washington but has to come from the American people themselves.

During a 21-minute eulogy delivered at the Marine Barracks Washington, Obama also warned that Americans must fight "a creeping resignation" about mass shootings, the notion "that this is somehow the new normal."

But "there is nothing normal about innocent men and women gunned down where they work," Obama said. "There is nothing normal about our children being gunned down in their classrooms."

In a sometimes emotional address, the president said he has now spoken at "five American communities ripped apart by mass violence," and added, "Once more, our hearts are broken; once more, we ask why."

Obama, who has proposed changes to the nation's gun and mental illness laws, noted that shootings in other countries such as Australia and the United Kingdom led to changes in their gun laws. "What's different in America," he said, "is it's easy to get your hands on a gun -- and a lot of us know this."

Obama has delivered sadly similar remarks after shootings at Fort Hood in Texas, an elementary school in Newtown, Conn., a movie theater in Aurora, Colo.; and a supermarket appearance by U.S. Rep. Gabrielle Giffords, D-Ariz., in Tucson -- and, now, Washington, D.C.

Just before his speech, Obama met privately with relatives of those who lost their lives during the Navy Yard attack. He told personal stories about the victims during his remarks, and again hugged many of their relative afterward.

Obama proposed a series of gun control laws after the Newtown shooting, including expanded background checks, but they have been blocked in Congress, mostly because of Republican opposition.

Many Republicans, and some Democrats, called the gun-control plans ineffective and an infringement on Second Amendment rights to gun ownership. GOP members said the emphasis should be on preventing the mental ill from obtaining guns.

Wayne LaPierre, executive vice president of the National Rifle Association, also cited inadequate security as another reason for Monday's shooting at the Washington Navy Yard, just a few miles from the U.S. Capitol and the White House.

Neighbors and tourists across the street from the Marine Barracks also debated the gun-control issue.

Jake Kennedy, who had traveled down from Boston, said the shooting served as a reminder of how inefficient Congress has become -- it's now impossible to even talk about gun laws. After recent shootings at an elementary school, a neighborhood, a workplace and a movie theater, Kennedy said he wondered what it would take.

"This is a stalemate," he said. "A law doesn't need to restrict anyone's freedom, but this argument over military-style rifles is silly."

Alix Montes, who lives in Washington, said he is worried that people are so focused on guns -- and stressed that they should be -- that they miss all other aspects of the gun violence problem: Mental health, poverty, education, security and profiling in cases where the police shoot unarmed people.

"What do the schools look like?" he said. "What do homes look like? Racial profiling? In this case, did people do the right thing? What can they do to prevent it?"

He added, "We're human, so it's easy to find one thing to blame."

Authorities say Navy contractor Aaron Alexis, 34, arrived at work Monday morning, passed through security, assembled a shotgun in a men's room and began a shooting spree that left 12 people dead before he was fatally shot.

Witnesses say Alexis had a history of mental problems.

Nathan Sterling, a Washington bartender, said "it's too easy to get guns," but also cited reports that the Alexis had "heard voices" and tried to get help. "He tried reaching out and they didn't do anything," Sterling said. "it's unconscionable."

During the service inside the Marine Barracks, Obama noted that he has ordered a review of security at military installations, but changes in gun laws are necessary.

Another speaker, Washington Mayor Vincent Gray, echoed Obama by saying that "our country is drowning in a sea of guns." He called it "a fact of life which we must stop accepting."

Officials closed the memorial to the public amid tight security. Some 4,000 invitees attended, many of them military personnel and members of Congress.